package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import org.apache.logging.log4j.util.Strings;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Autowired
    private ISeckillVoucherService seckillVoucherService;

    @Autowired
    private RedisIdWorker redisIdWorker;

    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Autowired
    private RedissonClient redissonClient;

    //执行lua脚本
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    //创建一个阻塞队列
    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    //创建一个异步线程
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    //在当前类初始化完毕之后立即执行
    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    //创建一个线程任务
    private class VoucherOrderHandler implements Runnable {

        String queueName="stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    //1.获取消息队列中的订单信息
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed()));
                    //2.判断消息获取是否成功
                    if(list==null||list.isEmpty()){
                    //2.1如果获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                    //解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //3.如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //4.ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }
        //异常读取
        private void handlePendingList(){
            while (true) {
                try {
                    //1.获取pending-list队列中的订单信息
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0")));
                    //2.判断消息获取是否成功
                    if(list==null||list.isEmpty()){
                        //2.1如果获取失败，说明pending-list没有异常消息，结束循环
                        break;
                    }
                    //解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //3.如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //4.ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        ex.printStackTrace();
                    }
                }
            }
        }
    }

   /* //创建一个线程任务
    private class VoucherOrderHandler implements Runnable {

        @Override
        public void run() {
            while (true) {
                try {
                    //1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    //2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (InterruptedException e) {
                    log.error("处理订单异常", e);
                }
            }
        }
    }
*/
    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        //1.获取用户
        Long userId = voucherOrder.getUserId();
        //2.创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //3.获取锁
        boolean isLock = lock.tryLock();
        //4.判断是否获取锁成功
        if (!isLock) {
            log.error("不允许重复下单");
            return;
        }
        //获取代理对象（事务）保证事务提交之后再释放锁
        try {
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            lock.unlock();
        }
//        }
    }

    private IVoucherOrderService proxy;

    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //获取订单id
        long orderId = redisIdWorker.nextId("order");
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(), String.valueOf(orderId));
        //2.判断结果是否为0
        int r = result.intValue();
        if (r != 0) {
            //2.1不为0,代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }

        //3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //4.返回订单id
        return Result.ok(orderId);
    }

   /* @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString());
        //2.判断结果是否为0
        int r = result.intValue();
        if (r != 0) {
            //2.1不为0,代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //2.2.为0，有购买资格，把下单信息保存到阻塞队列中
        VoucherOrder voucherOrder = new VoucherOrder();
        //2.3.订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //2.4.用户id
        voucherOrder.setUserId(userId);
        //2.5.代金卷id
        voucherOrder.setVoucherId(voucherId);
        //2.6放入阻塞队列
        orderTasks.add(voucherOrder);
        //3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //4.返回订单id
        return Result.ok(orderId);
    }*/

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //5.一人一单
        Long userId = voucherOrder.getUserId();

        //5.1.查询订单(当订单已经存在时不能再进行下单了）
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        //5.2.判断是否存在
        if (count > 0) {
            //用户已经购买过了
            log.error("用户已经购买过一次");
            return;
        }

        //6.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock=stock-1") //set stock=stock-1
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0) //where id=?and stock=?
                .update();
        if (!success) {
            //扣减失败
            log.error("库存不足");
            return;
        }
        //7.创建订单
        save(voucherOrder);
    }
}


 /*   @Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠价
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if(voucher.getBeginTime().isAfter(LocalDateTime.now())){
            //尚未开始
            return Result.fail("秒杀尚未开始");
        }
        //3.判断秒杀是否已经结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            //已经结束
            return Result.fail("秒杀已经结束");
        }
        //4.判断库存是否充足
        if (voucher.getStock()<1) {
            //库存不足
            return Result.fail("库存不足");
        }
        Long userId = UserHolder.getUser().getId();
        //创建锁对象
        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        boolean isLock = lock.tryLock();
        //判断是否获取锁成功
        if (!isLock) {
            return Result.fail("不允许重复下单");
        }
//        synchronized (userId.toString().intern()) {
        //获取代理对象（事务）保证事务提交之后再释放锁
        try {
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            lock.unlock();
        }
//        }
    }*/

  /*  @Transactional
    public Result createVoucherOrder(Long voucherId) {
        //5.一人一单
        Long userId = UserHolder.getUser().getId();

        //5.1.查询订单(当订单已经存在时不能再进行下单了）
        int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
        //5.2.判断是否存在
        if (count > 0) {
            //用户已经购买过了
            return Result.fail("用户已经购买过一次！");
        }

        //6.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock=stock-1") //set stock=stock-1
                .eq("voucher_id", voucherId).gt("stock", 0) //where id=?and stock=?
                .update();
        if (!success) {
            //扣减失败
            return Result.fail("库存不足");
        }
        //7.创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        //7.1.订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //7.2.用户id

        voucherOrder.setUserId(userId);
        //7.3.代金卷id
        voucherOrder.setVoucherId(voucherId);
        save(voucherOrder);

        //8.返回订单id
        return Result.ok(orderId);
    }
}
*/